The opposition is a key concept in this endgame. The opposition refers to the situation where the two kings face each other on the same rank or file, with one square between them. The player who moves their king away from the center loses the opposition and can find themselves in a difficult position. The player who has the opposition can use it to control the board and prevent the other player from advancing their pawn.
The following diagram demonstrates the opposition:
As mentioned in the beginning, this kind of opposition is a zugzwang, so whoever is to move, loses the advantage. White to move means a draw, Black to move loses. That’s because Black will be forced to move sidewise or to the back rank, effectively losing the control of key squares (marked with the green dots).
As a general rule, White wins if at least any two of the following conditions are met:
- The white king is in front of the pawn.
- White has the opposition.
- The white king is on the sixth rank.
In the position above, conditions 1 and 2 are met (provided that White just made a move), so White wins.
Let’s show another situation with conditions 2 and 3:
Again, Black to move loses the control of the key squares:
- 1. … ♚d8 2. d7 ♚c7 3. ♔e7 and 4. d8♕
- 1. … ♚f8 2. d7 and 3. d8♕
What about conditions 1 and 3?
1. … ♚g8 2. ♔h6 ♚h8 3. g6 ♚g8 4. g7 ♚f7 5. ♔h7 and 6. g8♕
The following game clearly shows how the outcome can differ if one player chooses a wrong move:
The opposition is a key concept in this endgame, and understanding it is essential for any player who wants to win this endgame or ensure a draw as the defending party.